Electronic devices such as computers, media players, and cellular telephones typically contain audio jacks. Accessories such as headsets have mating plugs. A user who desires to use a headset with an electronic device may connect the headset to the electronic device by inserting the headset plug into the mating audio jack on the electronic device. Miniature size (3.5 mm) phone jacks and plugs are commonly used in electronic devices such as notebook computers and media players, because audio connectors such as these are relatively compact.
Audio connectors that are commonly used for handling stereo audio have a tip connector, a ring connector, and a sleeve connector and are sometimes referred to as three-contact connectors or TRS connectors. In devices such as cellular telephones, it is often necessary to convey microphone signals from the headset to the cellular telephone. In arrangements in which it is desired to handle both stereo audio signals and microphone signals, an audio connector typically contains an additional ring terminal. Audio connectors such as these have a tip, two rings, and a sleeve and are therefore sometimes referred to as four-contact connectors or TRRS connectors.
Audio signals are typically conveyed between electronic devices and accessories in analog form. For example, left and right audio tracks are typically conveyed to a stereo headset as analog signals using “left channel” and “right channel” wires in a headset cable.
Improving audio fidelity and supporting additional audio channels with this type of analog signaling scheme may be difficult or impossible without providing additional analog signal wires in the headset cable. Arrangements of this type may not be compatible with existing audio connectors.
It would therefore be desirable to be able to provide improved techniques for conveying signals such as audio signals between electronic devices and external equipment.